Narrowband O2 signal drop out - Chrome ECU v2

[Dougal]

Hi All,

I'm hoping to get some insight into my o2 sensor signal dropping whenever i have more than idle or cruise load. (when TPS 15%+)
When the car goes into closed loop to target 14.7:1 AFR i can see the 02 signal cycling (between 0.07 volts and 0.8 volts) but as soon as I give any throttle the 02 sensor goes to zero with the occasional blip of a o2 signal (0.5 volts etc...)

As I understand when the car is run outside closed loop parameters it will switch to open loop and use the maps in the rom (fuel map, maf smoothing table VE ?)

I am running a Montero 482 MAF which is scaled in my rom (similar to EVO 399 scaling)
My car is only using 1 x Narrowband o2 sensor. I have set the peripheries in the rom to ignore the front o2 sensor and run just the rear o2.

I have been tuning fuel from the LTFT Low and Mid using the MAF Smoothing table (VE).

My concern is that my fueling way way off and zero in my logs means that its leaning out past the fuel MAP.
My STFT always jumps to +12.5 % addition of fuel whenever i apply load and come out of closed loop and into open loop.
I am unsure if the zeroing out of the NB o2 sensor is reflecting this or its something else related to my MAF or basic tune
My LTFT Low and Mid seem good at near zero (see below attached log)

I'm hoping someone here can shed some light on this.


Attached is an extract of one of my datalogs showing the o2 signal dropping out and a extract from evoscan showing the o2 cycling when idling.

o2 sensor drop out.jpg
o2 sensor cycling.jpg

Also attached is one of the notes in Evoscan regarding o2 sensor signals for high loads that are below 0.7 volts.
How could i test that this is actually an issue caused by MAF iteslf?

EVOSCAN Note for 02 sensor.jpg

The Montero 482 MAF scaling, size and adder im using.
482 MAF scaling size and adder.jpg

Is this just a matter of adding more fuel via the MAF smoothing table (VE) at the load area's (above 100hz) that is there the o2 is showing zero volts?